


Praise is Key

by yastaghr



Series: Scribbling is its own Language - Oneshots [36]
Category: Undertale (Video Game)
Genre: Alternate Universe - Underfell (Undertale), Alternate Universe - Underswap (Undertale), Anal Sex, Banter, Bottom Underfell Sans (Undertale), Dom Underswap Sans (Undertale), Ecto-Genitalia (Undertale), Ecto-Penis (Undertale), Hand Jobs, Kissing, Light Dom/sub, Lube, M/M, Massage, Praise Kink, Showers, Smut, Sub Underfell Sans (Undertale), Underfell Sans (Undertale), Underfell Sans/Underswap Sans (Undertale), Underswap Sans (Undertale), paarfi mention
Language: English
Status: Completed
Published: 2021-01-10
Updated: 2021-01-10
Packaged: 2021-03-14 01:20:52
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,091
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/28663089
Author URL: https://archiveofourown.org/users/yastaghr/pseuds/yastaghr
Summary: Red has had a rough day. Blue knows just how to take care of him and let him unwind.
Relationships: Sans/Sans (Undertale)
Series: Scribbling is its own Language - Oneshots [36]
Series URL: https://archiveofourown.org/series/667640
Comments: 9
Kudos: 33





	Praise is Key

**Author's Note:**

  * For [armethaumaturgy](https://archiveofourown.org/users/armethaumaturgy/gifts).



> For @armethaumaturgy, I hope you enjoy this!

Blue knew instantly, by the sound of the door to their apartment slam closed, that Red had had a rough day. It wasn't a complete slam, not one of those that would shake the walls and make old Mr. Walski send yet another angry letter to the landlord. Would he ever learn that the landlord wasn't going to evict them over something as simple as a slammed door? Blue didn't think he ever would.

The second clue (as if he needed one) to Red's rough day was the state of his clothes. Blue's brow bones twitched. That was yet another set of gloves that Blue would have to replace, his shoes were an absolute mess of mud and oil, and Blue really didn't want to know what those shirt stains were.

The third and final clue that Blue got was Red's face. He looked exhausted, tense, and just about ready to either kill someone or hide under the bed. From his speed walk Blue could guess which.

Blue intercepted his datemate and, despite the grime on his shirt and pants, pulled him into a hug. "RED. STOP. YOU'RE HOME NOW. YOU DON'T NEED TO WORRY ABOUT ANYTHING, REMEMBER? I'M IN CHARGE HERE. LET ME TAKE CHARGE, RED. LET ME TAKE CARE OF YOU."

Red, stiff at first in his arms, slowly relaxed as Blue said the familiar mantra that was both a welcome and a command. Red had written it himself. Blue had supervised, of course, but it had mainly been Red.

As Red relaxed Blue began to tug at his clothes. Red moved with the tugs, letting him remove the outermost layer of grit and dirt and prepare him for more cleaning.

Blue was disgusted to discover that Red's briefs and undershirt, too, were soaked in the slime. What had Red got into? This stuff was going to take at least two washes to get out completely. Maybe even three. Blue would need to use his extra strength formula, too. He sighed. The worries of a proper dom; the kind who took care of his sub completely.

Blue tossed the gross clothes into the laundry basket as he carried a filthy Red into the bathroom. He'd earlier used his blue magic to turn on the shower; by now it had warmed to the perfect temperature. Red loved his showers basically scolding hot, and Blue agreed. It killed more germs that way.

Red's sigh when he stepped into the shower was more than worth the grime Blue was now covered in. He quickly stripped off his own clothes and stepped into the shower behind Red. He sighed, too.

Getting a secondary shower head had seemed like a ridiculously frivolous idea at the time, but oh, did Blue love it now. It meant that neither of them were cold or dry in the shower, and it ended up saving them a lot on their water bill because they could take a shower together. He'd congratulated Red in the best way possible: they'd spent a night on the couch watching Red's favorite chick flicks and eating zebra popcorn, then retreated to their bedroom for some sexy fun. Definitely worth it.

Once the majority of the dirt and slime had been washed off of both of them Blue turned around to face Red's back and said, voice as slick as silk, "AS YOUR LOVING DOM I INSIST THAT YOU LET ME WARM YOU UP. A MASSAGE IS JUST WHAT YOU NEED, RED. MAY I LAY MY HANDS ON YOU?"

Red nodded. Blue noted his posture and expression and decided that, no, he wasn't in subspace, he was just tired. Good. Blue didn't want Red to have to deal with subdrop later.

Blue stepped forward, his hands reaching for the oil-infused lotion they kept for just this purpose. He slathered the luscious substance all over his phalanges. Then he got to work. He started at the top of Red's body and worked his way down. Massaging the leylines and working out the kinks (Mweh heh heh!) was something he enjoyed. Red had a lot of them today. No matter. He would handle them all!

Blue's mouth did a great deal of work, too. Every time he successfully worked out a kink in Red's magic Blue drowned the spot in kisses. Perfectly according to his plan, Red grew both embarrassed and impatient and said, "why won't you just kiss me for real?"

Blue glanced up at him with a gleam in his eye that spoke of a truly great sense of humor. At least, that's what he thought. Red didn't agree. "I'LL ONLY DO IT IF YOU ASK NICELY, RED."

Red groaned. He and Blue loved each other to death, but their senses of humor were wildly different. "blue, please, kiss me for real. i'm not begging."

Blue sighed. Red never wanted to beg for him. He knew why, but that didn't stop him from longing for it. After everything that had happened to Red in Underfell it was no surprise that he didn't want to beg ever again. "I SUPPOSE THAT WILL HAVE TO BE ACCEPTABLE. TURN AROUND, PLEASE, RED."

Red happily turned around, his bare feet almost skidding on the tile floor of their shower. Blue caught him in both arms, dipped him as much as the small shower would allow, and kissed him. Then he kissed him again. And again. For a while, in fact.

Blue and Red were both more than a little addicted to kissing one another. Red loved the feeling of someone else's teeth against him, of knowing that they were trusting him to be so close. Blue was a fan of the tingling in his magic that Red set off. Either way, both were happy to kiss one another for long periods of time.

This time what woke them up from their shared dream of one another was the water. Their water heater was one of the European models that didn't have a tank. It was just... finicky. Neither of them could figure out why it shut off the warm water after one hour. It wasn't too annoying. For now.

They both sheepishly looked one another in the eye sockets, then stood up and finished washing off the soap. They hurried... but they also stole a few kisses here and there. Neither of them could wait for what was next.

When they'd finally toweled dry and made it to their bedroom, Red was showing a lot fewer symptoms of his bad day. He no longer looked so haggard, he was wide awake, and his expression was anticipatory. Blue knew his was, too. They both knew that sexy times in the bedroom were coming next and were absolutely ready to go.

"RED, PLEASE GET THE TOWEL FROM THE CLOSET WHILE I GET THE LUBE. I THINK I'D LIKE TO FUCK YOUR ASS TONIGHT," Blue said matter-of-factly.

His datemate grinned from ear to ear and moved as close to a run as he managed when his life didn't depend on it to the closet. Blue turned around after watching the magic of Red's ecto coalescing into an ass for him for a moment and dug in the bedside drawer for their current bottle of lube. The drawers, like the rest of the wood in the room, were made of bamboo. The linens were bamboo, too. Monsters were big into bamboo. It was so sustainable and useful.

"YOU KNOW, YOU HAVE THE SEXIEST ASS I'VE EVER SEEN, RED. THE WAY IT GENTLY CURVES IN ALL DIRECTIONS AND LIGHTS UP THE ROOM IS DELIGHTFUL," Blue said casually. When Red sputtered, he grinned. Red had a praise kink a mile wide, if not wider.

Blue spun around in time to see Red's expression. Red was blushing his namesake color (a bright cherry red in fact) and smiling like a giddy fool. The star-shaped eye lights strayed downwards. Red's dick acted like a giddy fool, too.

Red's dick was a pretty thing, although Blue rarely let him use it. He met eye lights with his datemate and said, clearly and deliberately, "AND YOUR DICK IS ADORABLE. I LOVE HOW SHORT IT IS. LENGTH ISN'T ANYWHERE NEAR WHAT IT'S CRACKED UP TO BE. I'D RATHER HAVE GIRTH ANY DAY. AND THE FOLDS AND RIDGES ARE SO TACTILE. I LOVE PLAYING WITH THEM. IN FACT, I THINK I'LL PLAY WITH THEM NOW. SIT ON THE BED, PLEASE, AND LET ME HEAR YOUR VOICE."

The skeleton he loved followed Blue's order and sat down so hard it was a good thing they had a soft bed. The whole thing bounced a bit thanks to the springs. Blue bit back a giggle. Cute.

Then he got back to the matter at hand. Red's dick was perked up nicely, and Blue didn't feel like he needed to do much to it yet. He added a bit of lube to make this more comfortable for both of them. Bone was not soft, and ecto was not smooth. That combination had led to disaster their first time together. Now they used lube.

Blue's phalanges dipped into the dot of lube and immediately it soaked into his bones. It felt good, hydrating even after a long shower. He didn't waste time. He wrapped his phalanges around Red's girth and listened to him sigh.

"THAT'S IT, LET YOUR WONDERFUL VOICE OUT FOR ME. I LOVE HEARING IT. IT'S SO SMOKY. I LOVE IT," Blue praised, pressing a quick kiss to Red's teeth.

"hng, why you gotta compliment me so good?" Red whined as Blue's hands slowly started pumping his dick.

"BECAUSE YOU ARE WORTH EVERY COMPLIMENT I COULD GIVE YOU, RED," Blue said truthfully. He really meant it. Red was wonderful, and Blue wanted him and everyone else around to know it. Not right now, obviously, though. There really shouldn't be anyone around right now but them.

Blue didn't give him a chance to respond, though. He sped up his pace with his hands, giving Red a slightly rougher hand job - just the way he liked it.

"FEELING GOOD, RED?" Blue asked, "MAY I PREPARE YOU FOR THE MAIN COURSE?"

Red grinned through his lazy, fucked expression and leaned over to kiss Blue. "sure thing, babe. go soft on me, you know how sensitive i am back there."

Blue nodded, taking a brief moment between pumps to squirt a generous dollop of lube onto his other hand. Red's eye lights gleamed nervously as he watched it. Blue didn't want that, so he sought to reassure him. "IT'S OKAY, RED. WE DON'T HAVE TO DO THIS IF YOU DON'T WANT TO. TONIGHT IS SUPPOSED TO BE ABOUT YOU, AFTER ALL. I WANT YOU TO BE HAPPY AND RELAXED."

Red chuckled a bit at that and kissed Blue again, deep and slow this time to match his calmer mood. "i ain't worried, blue. i'm just a bit nervous after last time. you're sure i'm not going to react to this lube, ain't you?"

"I'M SURE. YOUR PENIS HASN'T REACTED, SO WHY WOULD YOUR ASS? I KNOW LAST TIME WAS PAINFUL, SO I MADE TRIPLE SURE NOT TO GET THAT LUBE AGAIN."

"you've got a point," Red slowly said. Then he nodded decisively and said, "okay. go ahead and prep me, babe."

Blue stole a quick kiss from him, then set to work. He carefully introduced his smallest finger into Red's puckered asshole. Blue, unfortunately, had rather fat fingers, so even his smallest finger was huge. Red gasped and his fingers dragged a small corner of the towel into a ball. Blue stopped moving the moment he heard that gasp. He just held his finger there, covered in lube and inserted maybe a quarter of an inch into his lover's ass.

"ARE YOU DOING OKAY, RED?"

"am i doing okay?" Red said, frustrated, "i'm fine except you ain't moving! i'm not that delicate, you know."

Blue grinned. There was that snark he loved. He started wiggling his finger deeper into Red's ass. He loved how it felt inside. Red was so soft! "I KNOW THAT, RED. YOU'VE DEMONSTRATED IT MORE THAN ONCE. I ONLY WAS BEING CAREFUL WITH YOU BECAUSE I KNOW YOU HAD A VERY ROUGH DAY TODAY."

"yeah, but it's because of that rough day that i want you to hurry up! like you said earlier, i need this. give it to me, darn it!" Red complained.

Blue cheekily scolded him, and, playing off an old inside joke that Red was only allowed to swear during sex, said, "LANGUAGE!"

Red grinned, loving that joke, "sorry, blue. i should have said, 'give it to me, damn it!'"

Blue grinned back at him, basking in the joy radiating off of his lover and also his accomplishment. "THAT'S RIGHT. THAT'S EXACTLY WHAT YOU SHOULD HAVE SAID. YOU'VE TAKEN MY WHOLE FINGER NOW, RED. ARE YOU READY FOR ANOTHER ONE?"

"fuck yes i'm ready for another one!" An exasperated Red said, "i've been asking nothing else for an hour!"

"HAVE YOU BEEN READING PAARFI AGAIN?" Blue asked suspiciously as he lubed up his second smallest finger. Red might be confident he was ready, but that didn't mean that Blue wouldn't go easy on him. He loved Red. He didn't want to hurt him.

"maaaaaybe," Red answered, his sly grin raising Blue's suspicions even higher, "what of it?"

Blue slipped his finger into Red's ass at the same time as he ordered, "YOU WILL NOT READ AHEAD IN THE SERIES WITHOUT ME. I DO NOT WANT YOU TO SPOIL ME LIKE LAST TIME. IS THAT UNDERSTOOD?"

Red squeaked and bobbed his head in a nod so fast his neck popped. "i won't! i won't!"

Blue smiled and split his fingers apart to stretch Red, making his squeak turn into an even higher squeal. "GOOD," he said as he pressed his teeth to Red's in a skeleton kiss, "NOW, I'M GOING TO SPEED UP MY PREPARATIONS, BECAUSE ALL YOUR CHEEK HAS MADE ME HARD AND I WANT TO CUM. HOW CLOSE ARE YOU?"

Red's answer burbled out, almost tumbling out of his mouth faster than Blue's fingers worked him. "really close, blue!"

"GOOD. I WANT YOU TO GO AHEAD AND CUM WHEN YOU NEED TO, OKAY? TONIGHT IS ABOUT YOU, AFTER ALL. I THINK YOU'RE WIDE ENOUGH TO TAKE ME NOW, SO I'M GOING TO GET LUBED UP. DO YOU WANT ME TO GO IN FAST OR SLOW?"

"...slow, please?" Red asked quietly, surprising Blue. He quickly explained, "i know i usually like it fast, but my body is still pretty sore after everything that happened today. do you mind if we go slow?"

Blue smiled softly at his lover, pressing a series of soft kisses to his neck. In between each kiss he said a word of, "OF COURSE I DON'T MIND, RED. I LOVE AND RESPECT YOU."

Red's little breathless giggles and the buzzing of his embarrassed magic against Blue's skull were wonderful to feel. He loved getting to make Red flustered like this. He loved that no one but him was getting to see it right now.

While he was teasing his lover's vertebra with his tongue, Blue released his dick. He didn't leave it completely alone, though. He used his blue magic to squeeze it ever so slightly, doing so in a rhythm that would please Red. They'd played around with this once for hours. This rhythm was the winner.

The hand that had been pumping Red this whole time, now freed, shook itself out quickly to get the magic flowing right again before slathering itself up in a fresh coat of lube. Then, with the aid of his blue magic, Blue pulled his dick up and covered it in enough lube to grease a wheel. Red and he both liked a smooth fuck, so lots and lots of lube was essential. They went through a lot of lube.

Then, dick lubed almost to an inch thicker than it was, Blue lined it up with Red's asshole and sank in. He'd used his magic to maneuver Red onto his hands and knees. This position gave him more control over what he was doing. He slid in agonizingly slowly. Then he waited for Red's go ahead like a good dom.

"would you just fuck me already?!!" Red complained in a few minutes. At least, it felt like minutes to Blue. It was probably closer to a minute and a half. That was still longer than Red usually took, but not as long as the very first time.

Blue's smile spread across his face so widely that it hurt his skull. It was mostly annoyance. He was ready to go awhile a go. "OF COURSE, RED."

Then Blue began moving. He was definitely too slow at first, going about the same pace as water dripping off a wet roof after a light rain. Then he sped up, slowly moving through the tempos until he reached one that fit. It felt like the same speed as a mule walking very slowly on the edge of a canyon in a national park.

That's what Blue felt like right now. A creature on the edge of a huge drop off that would feel like an amazing rush. He hoped he would land in the river instead of on solid stone, but there was always a chance for either. It was almost always water, though.

It didn't take long before Red was squeezing him tightly. The sounds of splattering cum filled his ears along with the lovely whine Red made when he came. It triggered Blue's own orgasm; definitely a good one.

When they both had grunted and whined their way to the end of their orgasms, Blue carefully pulled out and laid them both down on a clean part of the giant towel. He quickly settled them in their favorite cuddling position: face to face, but with Red's head pressed into Blue's shoulder. They both sighed and relaxed into each other.

"that was perfect, blue," Red said eventually, his words not so much breaking the comfortable silence as they were enriching it.

"THANK YOU, RED. I ALWAYS TRY," Blue said, blushing at the praise to his own skills, "AND I ALWAYS WANT TO TAKE CARE OF YOU AFTER. YOU KNOW THAT. DO YOU WANT TO TAKE ANOTHER SHOWER OR A BATH THIS TIME? AFTER WE CUDDLE, OF COURSE. YOU ARE AN EXCELLENT CUDDLER."

Red smiled softly back at him, his own blush overtaking him. "thanks, babe. i think i want a bath now."

"UNDERSTOOD. I LOVE YOU, RED."

"i love you, too."

**Author's Note:**

> You can find me on:
> 
> https://yastaghr.com  
> https://twitter.com/yastaghr *most used  
> https://yastaghr.tumblr.com


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